Hi,
WDSO does not have the "delta" which is similar to Standard DSO..Its delta is based on the requests not yet loaded..
You may refer in these docs..
Prem-(Sap BW Powered Hana): A Few More Tips on Write Optimized DSO
http://learnsapbibasics.blogspot.com/2013/04/when-we-use-write-optimized-dso.html
Regards,
Loed